The present invention relates to devices which lift toilet seats and commode seats by foot action or through mechanical or electronic devices such as a sound recognition device so as to avoid the use of the hands. In particular, the present invention is directed to toilet seat elevator systems that utilize a foot operated pedal, a sound recognition device, or a combination thereof, to raise and lower the toilet seat.
Systems for the hands-free operation of raising a nd lowering of toilet seats are useful for a number of reasons. The majority of men raise the seat of a toilet to urinate from a standing position, and so must lift the seat prior to the majority of uses. Both men and women lift the seat when cleaning the toilet bowl. Many people consider a toilet seat to be slightly disgusting or a vector for disease, and so dislike touching a toilet seat with their hands. Some people use their feet to move the seat, which is awkward and tends to dirty the seat. Thus, a toilet seat lifter or elevator system that allows hands-free operation is not only a convenience, but also permits a more sanitary operation.
In the majority of toilets, the toilet bowl has bolt holes at the rear that are used for attaching the bowl portion with the seat, which the user sits on, and the seat cover or lid, which closes the bowl by covering the opening in the seat. The cover and the seat are independently hinged, usually on the same hinge axis. In most toilets, when the seat is fully lifted, the center of gravity of the seat moves past the vertical, balanced position directly over the hinge axis to a position to the rear of the hinge axis. This means that the seat, when fully lifted and rotated backward, leans against the toilet water chest or the wall behind the bowl, and is stable. To lower the seat after urination or cleaning, the hands must be used again to pull the seat past the vertical balanced position to a forward-leaning position in which gravity can pull the seat down to the closed position.
Many men fail to lower the seat after raising it to urinate. Women are often upset by this common failure of men; women seldom raise the seat themselves and so tend to assume that the seat will be in the lowered position when they go to use the toilet. Women are thus likely to sit on the toilet without checking to see if the seat is down, and therefore are likely to sit directly onto the toilet bowl if the seat has been left in the lifted position, risking injury. Therefore, it is desirable for a mechanism that lifts the seat to also lower it automatically.
Yoke et al., in U.S. Pat. No. 5,153,946, disclose an invention which automatically lowers the seat some time after it has been lifted. The device is incorporated into the hinge of the seat and contains a timer, activated by the raising of the seat, that rotates the seat past the vertical point so that gravity can carry it back to the closed position. This invention, however, does not disclose a hands-free method of lifting the seat.
In contrast to the Yoke patent, the seat-raising mechanism in the present invention is so designed that men who wish to urinate standing up can lift the seat by stepping on a foot pedal next to the toilet and urinate while standing on the pedal. When they are finished urinating and release the pedal, the seat should automatically fall back down.
The simplest way of lowering the seat automatically after use is to use gravity. If a seat-raising mechanism does not rotate the seat past the vertical balanced position when it lifts the seat, then the seat will return to the closed position under gravitys force if the mechanism allows it. The design should allow the seat to be rotated past the balance point to a rearwardly-inclined angle, since the seat should remain open by itself for cleaning of the bowl, emptying buckets into the bowl, and so on.
Foot-operated seat lifters which can hold the seat in an inclined position for automatic closure by gravity have been used by several inventors. For example, Daniel Robbins, in U.S. Pat. No. 5,075,906, teaches a foot-operated seat lifter which holds the seat to a forwardly-inclined position. The mechanism consists of a base resting on the floor beside the toilet, a pedal hinged to the base, and a linkage of three members connecting the pedal to the seat. A total of six hinges is used for the pedal and linkage. Besides the complexity of five moving parts and six hinges, another drawback is that the Robbins device has no adjustments to allow its use with toilets of differing design. Moreover, it appears in his FIG. 1 that the base of the device is likely to move when the seat is fully opened to a rearward position for cleaning. When the pedal of the Robbins device is fully depressed, the seat is in the forwardly-inclined position as shown in FIG. 1; if the seat were moved to the rearwardly-inclined position, then the base would be lifted off the floor and moved to the left in the drawing figure. This is due to the fact that the linkage connecting the base to the seat is angled. If the base hinge were more directly under the seat hinge, then the base would be less likely to move.
U.S. Pat. No. 4,649,576, issued to David Lillie, discloses a seat lifter which is simpler than the complex device of Robbins. Instead of an immoveable base, Lillie uses a rocker block which combines the base and pedal into one block of wood or plastic. The user steps on one end of the block, which rocks backward under the force. The other end of the block moves upward. A vertical arm is attached to that end, so that stepping on the block lifts the arm. The upper end of the arm is connected to the seat. Lillie's vertical arm is adjustable in length (see FIG. 2). An eye bolt 212 screws in and out of the vertical arm 104 to vary the length. Since the eye bolt is also free to rotate in the vertical arm 104, and can also rotate substantially to and fro due to its loose fit on the flanged end 222, the rocker block 100 at the lower end of the arm is likely to rotate out of its proper position (as well as sliding out of its proper position on the floor, like the base of Robbins' device). Indeed, Lillie advises that a strap 324 on the block be nailed or glued to the floor to hold the rocker block 100 in position. The Lillie device has only one adjustment, the length of the arm.
Pilkington et al., in U.S. Pat. No. 4,030,146, describe a seat lifter with a base, a pedal, and an upright arm joining the pedal to the seat. Like the Robbins invention, the Pilkington device has no adjustments whatsoever. Accordingly, the device will not function with various toilet heights. Even a small variation in floor height will cause a variation of the angle of the raised seat when, as shown in their FIG. 1, the end 60 of the pedal 16 is fully depressed to the floor. Moreover, a tilt of the floor can cause the whole Pilkington device to be thrown askew, and possibly to jam as undue torque is put on the hinges of the device.
L. D. Svedelius, in U.S. Pat. No. 1,999,070, also shows a seat lifter which can maintain the seat in a forwardly-inclined position. It is not adjustable.
None of the patents listed above has any provision for varying the force required on the pedal to lift the seat. That is, none has any means for varying the ratio between the foot force applied to the foot end of the pedal member and-the seat-raising force applied by the upper end of the arm to the toilet seat. Thus, these inventions will not work equally well with toilet seats of various weights. Toilet seats are made of everything from solid oak to vinyl-covered urethane foam and they vary widely in weight. The functioning of these inventions will vary accordingly.
Several of the above devices, and other previous inventions, include a mechanism for cushioning the shock of a toilet seat which falls down onto the toilet bowl. For example, the Lillie invention uses a bellows to cushion the fall with compressed air; Pilkington et al. employ a U-shaped spring to prevent slamming. However, such complications are not needed. Toilet seats are designed to be dropped in normal use, and seldom break despite the rough usage they receive.
While energy absorption is not needed in a seat lifter of the type described above, resilience is. The reason is that, when a user steps onto the pedal of the device, the initial force must be greater than the force applied a short time later, for two reasons. First, the mechanical advantage is least when the seat is horizontal and the center of gravity of the seat is farthest from the seat hinge; second, the inertia of the seat must be overcome and extra force is needed at the beginning of the upward motion of the seat.
If the entire mechanism is rigid, like those discussed above, then the user who steps onto the pedal may sense from the high resistance of the pedal that a large force is needed. He may then push too hard, causing the seat to fly past the desired point and crash into the wall or water chest.
If a portion of the mechanism is resilient, then any excess force will compress the resilient member. The user, sensing a softer pedal, will tread less hard. The energy stored in the resilient member will be recovered as the seat swings up. Resilience in the mechanism is thus a means for varying the mechanism's dynamic leverage, that is, the instantaneous ratio between the force applied to the foot end of the pedal member and the force applied by the upper end of the arm to the toilet seat, while the seat is accelerating. The act of raising the seat by stepping on the pedal creates a dynamic situation, in which the acceleration of the seat affects the forces. It is to be contrasted with the static leverage that applies when the seat is held in at a fixed angle by foot pressure. A resilient member in the linkage will not vary the static leverage, but it will vary the dynamic leverage.
Pilkington et al., as mentioned above, include a resilient U-shaped member 14 or 50 in their device to cushion the shock of the falling toilet seat. This U-shaped member is not part of either the pedal or the arm, but is rather connected in between them. Being resilient, it is not an energy absorber or damper. It apparently serves to pre-load the mechanism toward a seat-raised position. Pilkington et al. state at column 3, line 58: "[T]he member 50 . . . due to its resilient characteristics it serves as the bowed member 14 . . . which serves to bias the rear portion of the pedal 16 in an upward direction." At column 4, line 5, they continue: "When the foot is removed, the seat 22 falls . . . however, due to . . . force exerted by the bowed member 14, the seat is prevented from slamming." The member 14 or 50 is stressed in the seat-down position, exerting an upward force on the rear end of the pedal, and reducing the force needed to begin pushing the pedal down.
S. Kuno, in U.S. Pat. No. 1,505,472, shows a seat lifter which employs a curved arm and coil springs 19 and 20 mounted between the pedal and the arm. The springs, acting with a third rigid member between the pedal and arm, force the seat toward an intermediate position. While Kuno does not explain the mechanism, the provision of the springs and the slot in the curved arm in which a pin of the third member rides, imply that the curvature of the arm is not related to any resilient quality of the arm. Kuno shows a simple mechanism with coil springs in U.S. Pat. No. 1,509,242.
U.S. Pat. No. 4,862,525 to Cheng shows a lifter with a coil spring in the base which exerts a lifting force in the initial portion of the lift, and then exerts no force.
U.S. Pat. No. 1,501,177, issued to B. Ozwirk, shows a telescopic friction damper between the pedal and the arm.
The springs disclosed in these patents are ill-suited to adjusting the dynamic leverage. One reason is that they obey Hooke's Law. Hooke's Law is said to be obeyed when a spring's deflection is directly proportional to the force that causes it to deflect. Coil springs are well-known for obeying Hooke's principle, and the U-shaped spring of Pilkington et al. also approximates it well, Hooke's Law is disobeyed by many resilient objects. A slightly bowed rod or plate, for example, is quite stiff when it is straight; as it begins to bend, its increasing curvature makes it less stiff. The ratio of force to deflection is not constant. Simple experiments with a 3 by 5 card or a bendable ruler will verify this.
Springs which are stressed in the seat-closed position exert a force on the pedal that reduces the force to be exerted by the users foot but does not affect the dynamic leverage of the mechanism. Reduction in static force is not needed because a person, who outweighs a toilet seat by at least ten to one, can easily exert more than enough force on the pedal to lift the seat; the user's problem is control of the stepping force. Force must be applied smoothly to avoid over-accelerating the seat and banging it back against the wall or water chest.
The prior art is not seen to disclose any seat lifter of the pedal and arm type which incorporates dynamic or static leverage adjustment.